Ed Miliband is still "clinging to the pretence" that Labour can secure a majority at the general election, according to Nicola Sturgeon.
The SNP leader said her party was open to a "confidence and supply" deal (a vote-by-vote arrangement) with Labour after the election.
"[Miliband] is still clinging to the pretence he has got some chance of winning an overall majority," the First Minister of Scotland said.
"We have got vast experience as a minority government the principles are the same. You have to build alliances, you have to win votes on a case-by-case basis."
She also told the BBC Radio 4 Today show: "It would be far better than what usually happens to Scotland at Westminster, which is we are ignored or side-lined.
"The bottom line here is, if Scotland wants to have that influence, that power, that clout in Westminster, the only way get it is to vote SNP.
"If there is real SNP strength in the House of Commons we can force progressive change."
The remarks come after Miliband ruled out a coalition government with Sturgeon's party following the 7 May vote.
"Now the Tories are doing something else, the party that haven't won a majority for over 20 years and are running a misleading campaign based on the idea of a Labour/SNP coalition," the Labour leader said.
"As I said on Thursday night this idea is nonsense. It will not happen. There are big differences between us on a whole range of issues, not just on the integrity of the UK and on another referendum but on fair funding between the countries of the UK and fair taxes.
"In continuing to repeat this claim, the Conservative Party and David Cameron are simply trying to scare people. Labour will not go into coalition government with the SNP. There will be no SNP ministers in any government I lead."
The SNP are set to take a swathe of seats from Labour at the election and scupper Miliband's chances of becoming Prime Minister outright.
The party currently hold six out of 59 Scottish seats in the House of Commons, but a recent Survation poll predicted that the SNP are set to double their share of the vote when compared to 2010.
The figures mean around 41 of Labour's Scottish constituencies are at risk of swinging to the SNP.